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Spatial Pattern Evolution and Influencing Factors of Cold Storage in China 被引量:4
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作者 LI Jinfeng XU Haicheng +2 位作者 LIU Wanwan WANG Dongfang ZHOU Shuang 《Chinese Geographical Science》 SCIE CSCD 2020年第3期505-515,共11页
Cold storage is the vital infrastructure of cold chain logistics. In this study, we analyzed the spatial pattern evolution characteristics, spatial autocorrelation and influencing factors of cold storage in China by u... Cold storage is the vital infrastructure of cold chain logistics. In this study, we analyzed the spatial pattern evolution characteristics, spatial autocorrelation and influencing factors of cold storage in China by using kernel density estimation(KDE), spatial autocorrelation analysis(SAA), and spatial error model(SEM). Results showed that: 1) the spatial distribution of cold storage in China is unbalanced, and has evolved from ‘one core’ to ‘one core and many spots’, that is, ‘one core’ refers to the Bohai Rim region mainly including Beijing, Tianjin, Hebei, Shandong and Liaoning regions, and ‘many spots’ mainly include the high-density areas such as Shanghai, Fuzhou, Guangzhou, Zhengzhou, Hefei, Wuhan, ürümqi. 2) The distribution of cold storage has significant global spatial autocorrelation and local spatial autocorrelation, and the ‘High-High’ cluster area is the most stable, mainly concentrated in the Bohai Rim;the ‘Low-Low’ cluster area is grouped in the southern China. 3) Economic development level, population density, traffic accessibility, temperature and land price, all affect the location choice of cold storage in varying degrees, while the impact of market demand on it is not explicit. 展开更多
关键词 cold storage spatial pattern evolution kernel density estimation(KDE) spatial autocorrelation analysis(SAA) spatial error model(SEM) China
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Temporal and spatial evolution of global major grain trade patterns
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作者 Ziqi Yin Jiaxuan Hu +3 位作者 Jing Zhang Xiangyang Zhou Lingling Li Jianzhai Wu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第3期1075-1086,共12页
The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain ... The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain trade from 1990 to 2020, focusing on network topology, centrality ranking, and community structure. There are three major findings. First, the global major grain trade network has expanded in scale, with a growing emphasis on diversification and balance. During the study period, the United States, Canada, China, and Brazil were the core nodes of the network. Grain-exporting countries were mainly situated in Asia, the Americas, and Europe, and importing countries in Asia, Africa, and Europe. Second, a significant increase in the number of high centrality countries with high export capacity occurred, benefiting from natural advantages such as fertile land and favorable climates. Third, the main global grain trade network is divided into four communities, with the Americas-Europe community being the largest and most widespread. The formation of the community pattern was influenced by geographic proximity, driven by the core exporting countries. Therefore, the world needs to enhance the existing trade model, promote the multi-polarization of the grain trade network, and establish a global vision for the future community. Countries and regions should participate actively in global grain trade security governance and institutional reform, expand trade links with other countries, and optimize import and export policies to reduce trade risks. 展开更多
关键词 grain trade pattern evolution complex network
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Evolution characteristics of hydrological connectivity pattern of marsh wetland in Naoli River Basin
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作者 WANG Haonan HOU Guanglei +1 位作者 YANG Changbao SONG Xiaolin 《Global Geology》 2021年第2期95-102,共8页
As an important indicator of the structural and functional stability of wetland landscapes,hydrological connectivity plays an important role in maintaining the stability of wetland ecosystems.Large-scale human activit... As an important indicator of the structural and functional stability of wetland landscapes,hydrological connectivity plays an important role in maintaining the stability of wetland ecosystems.Large-scale human activities have led to significant changes in the hydrological connectivity pattern of wetlands in Naoli River Basin since 1950 s.Combined with the availability of wetland habitat and the spreading capacity of aquatic birds,hydrological connectivity indices of marsh wetlands were calculated in the studied area,and the temporal and spatial changes were analyzed from 1950 s to 2015.The results indicate that:(1)the hydrological connectivity index of the marsh wetlands shows a growth trend with increasing distance threshold.All patches of marsh wetlands linked together when the distance threshold reached 35--40 km;(2)the optimal distance of hydrological connectivity is about 10 km for marsh wetlands of whole Naoli River Basin;(3)the total hydrological connectivity of marsh wetlands decreased in the Naoli River Basin from 1950 s to 2015.Although the hydrological connectivity index increased after 2005,the fragmentation of the landscape has not been improved.The analysis of the wetland hydrological connectivity can provide a scientific basis for the ecological restoration and protection of the wetland in the Naoli River Basin. 展开更多
关键词 Naoli River Basin hydrological connectivity pattern evolution distance threshold
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Dynamic evolution patterns of the degree of ground resistivity anisotropy and the sets mogenic process 被引量:1
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作者 毛桐恩 胥广银 +2 位作者 范思源 赵明 孙景芳 《Acta Seismologica Sinica(English Edition)》 CSCD 1999年第2期200-205,共8页
Following a new train of thinking, this paper has explored first the potential information in the ground resistivitydata observed by the existing geoelectric observation system, investigated and proposed a new dimensi... Following a new train of thinking, this paper has explored first the potential information in the ground resistivitydata observed by the existing geoelectric observation system, investigated and proposed a new dimensionlessgeoelectric precursor factor, the degree of ground resistivity anisotropy, S, and studied the characteristics of dynamic evolution pattern of S during the seismogenic process. The results show that, during the seismogenic process, the degree of ground resistivity anisotropy (S) displays h process of 'normal' → 'abnormal strengthening(amplitude, range)' → 'abnormal weakening'→ 'earthquake occurrence'→ 'normal'. The earthquake wouldoccur at the time when the S value has entered the late stage of strengthening and turns to weaken and in the gradient belt on the margin ofS anomaly region. The dynamic evolution pattern ofS reflects the changes of the tectonicstress field during the seismogenic process. Therefore, it would be possible to trace the process of earthquake generation and occurrence from the dynamic evolution pattern ofS so as to service eaJ'thquake prediction. 展开更多
关键词 degree of ground resistivity anisotropy dynamic evolution pattern seismogenic process
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Quantum Adiabatic Evolution for Pattern Recognition Problem
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作者 E.Rezaei Fard K.Aghayar 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第12期6-10,共5页
Quantum pattern recognition algorithm for two-qubit systems has been implemented by quantum adiabatic evolution. We will estimate required running time for this algorithm by means of an analytical solution of time- de... Quantum pattern recognition algorithm for two-qubit systems has been implemented by quantum adiabatic evolution. We will estimate required running time for this algorithm by means of an analytical solution of time- dependent Hamiltonian since the time complexity of adiabatic quantum evolution is a limitation on the quantum computing. These results can be useful for experimental implementation. 展开更多
关键词 Quantum Adiabatic evolution for pattern Recognition Problem
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Impacts of land use change on landscape patterns in mountain human settlement:The case study of Hantai District(Shaanxi,China) 被引量:2
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作者 WANG Lei WU Lian ZHANG Wei 《Journal of Mountain Science》 SCIE CSCD 2021年第3期749-763,共15页
Mountain area is an important geographical unit of land,and its ecology is sensitive and fragile.Over the past few decades,human activities have caused dramatic changes in land use in mountainous areas,which caused ch... Mountain area is an important geographical unit of land,and its ecology is sensitive and fragile.Over the past few decades,human activities have caused dramatic changes in land use in mountainous areas,which caused changes in landscape patterns and impacts on the ecological environment.It is unknown how the mechanism of land use affects the landscape pattern at different scales.The Hantai District,a typical human settlement in the mountain area in Shaanxi,China,was chosen as the study area.Based on the remote sensing images,the mathematical models and landscape indexes were adopted to evaluate the impact of land use change from 1998 to 2017 on the landscape pattern at different scales,and its main driving forces were analyzed.The results showed that the urbanized land expanded largest from 15.39%to 24.30%,and cultivated land experienced the largest decline from 43.54%to 35.35%.Changes in land use have made the patch morphology of most land types developed from a natural random to a sawtooth shape,and its spatial pattern evolved from a ruleset to a fragmented expansion.This reflects the continuous strengthening of human intervention in the process of regional development.Under the jurisdiction of Hantai District,the biggest change in landscape pattern is in Hanzhong City and Qili Town.The improved economy and increasing population and urbanization rate were the main factors that cause these changes.This research could provide necessary information for understanding the evolution mechanism of land resources in mountainous human settlements for mountainous areas with significant geomorphic differentiation. 展开更多
关键词 Land use change Land cover change Landscape pattern evolution Transition trend Driving force Mountain regions Hantai District
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Optical patterns in spatially coupled phase-conjugate systems
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作者 岳立娟 桑金玉 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期187-193,共7页
Various pattern evolutions are presented in one- and two-dimensional spatially coupled phase-conjugate systems (SCPCSs). As the system parameters change, different patterns are obtained from the period-doubling of k... Various pattern evolutions are presented in one- and two-dimensional spatially coupled phase-conjugate systems (SCPCSs). As the system parameters change, different patterns are obtained from the period-doubling of kink-antikinks in space to the spatiotemporal chaos in a one-dimensional SCPCS. The homogeneous symmetric states induce symmetry breaking from the four corners and the boundaries, finally leading to spatiotemporal chaos with the increase of the iteration time in a two-dimensional SCPCS. Numerical simulations are very helpful for understanding the complex optical phenomena. 展开更多
关键词 pattern evolution phase-conjugate one- and two-dimensional spatially systems
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Evolution of 3D tectonic stress field and fault movement in North China
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作者 陈连旺 陆远忠 +2 位作者 郭若眉 许桂林 张杰 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2001年第4期371-383,共13页
Based on data of fault movement surveying, we simulate the evolution process of three dimensional stress field in North China by three dimensional finite element method. Evolutional patterns in one-year time scale fro... Based on data of fault movement surveying, we simulate the evolution process of three dimensional stress field in North China by three dimensional finite element method. Evolutional patterns in one-year time scale from 1986 to 1997 have been illustrated and the evolution characteristics of stress field have been analyzed. In comparison with the seismic activity among that time interval in North China, we have primarily discussed the relationship between the evolution of stress field and seismic activity. 展开更多
关键词 North China fault displacement tectonic stress field evolutional pattern 3D finite element model
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Temporal and Spatial Evolution of Lakes in the Bashang Plateau for Nearly Recent 30 Years
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作者 Xiujuan Li Sugai Gao +2 位作者 Wenli Li Guifu Qiu Zhiyuan Tian 《Journal of Water Resource and Protection》 CAS 2022年第10期698-708,共11页
Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 198... Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 1984 to 2015 were selected to monitor the area of lakes in the Bashang Plateau and to analyze the spatiotemporal evolution and driving forces of lakes in the Bashang Plateau. The results showed that there were 47 lakes in the Bashang Plateau in 2015, with a total area of 37.63 km2, mainly distributed in the central and western regions of the region. From 1984 to 2015, the lakes in Bashang Plateau showed a shrinking trend. At the same time, there are obvious stage differences in lake changes. During 1984-1996, the number of lakes increased by 99 and the total area increased by 124.43 km2. From 1996 to 2015, the number of lakes decreased by 142, and the total area decreased by 183.96 km2. Before 1996, climate change was the dominant factor. However, the shrinkage of lakes after 1996 is the result of climate change and human activities. Among them, the large-scale planting of water consuming crops such as vegetables is the main human activity mode leading to lake shrinkage. This study will help to understand the expansion and contraction factors of the Bashang Plateau lakes in Hebei province and provide a reference for the future protection and management of the lakes. 展开更多
关键词 Bashang Plateau Lake Area Spatial and Temporal patterns evolution Driving Force
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Does the Belt and Road Initiative Promote Value Chain Connection Between China and the Silk Road Countries? 被引量:1
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作者 ZHENG Zhi LIU Weidong SONG Zhouying 《Chinese Geographical Science》 SCIE CSCD 2021年第6期979-995,共17页
The global value chains have become the core skeleton of the global economy.As a large-scale international cooperation initiative,the Belt and Road Initiative(BRI hereafter)may have a significant impact on the global ... The global value chains have become the core skeleton of the global economy.As a large-scale international cooperation initiative,the Belt and Road Initiative(BRI hereafter)may have a significant impact on the global economic landscape.In this context,the spatiotemporal pattern and evolution of the value chain connection of the Silk Road countries and whether the BRI will promote the value chain connections between China and these countries are important research questions for understanding the changing global economic landscape.This paper employs input-output analysis,network analysis and difference-in-differences based on Propensity Score Matching(PSM-DID)to conduct an in-depth quantitative study of these questions.The results show that,first,the overall value chain connection between China and the Silk Road countries has been rising since 2001.From the perspective of geographical distribution,Southeast Asia is the highest value chain connection region with China,and the growth in the central and eastern Europe is the most significant,whereas the central Asia is the lowest value connection region.From the perspective of complex network analysis,China’s position in the network of value flow among the Silk Road countries has been increasing continuously,and it has been in the lead position since 2008.Besides,the implementation of the BRI has had a significant positive influence on the overall value chain connection between China and the Silk Road countries,but this positive influence is limited to the central and eastern Europe region,whereas it is not significant in other regions.Finally,this paper suggests that to promote the development of value chain connection,the Silk Road countries need to develop more specific policies related to value chains.Policymakers need to be able to correctly identify the comparative advantages of the region and the types of value chains that are compatible with them and then find suitable partners and formulate targeted promotion policies. 展开更多
关键词 the Belt and Road Initiative global value chains input-output technique pattern evolution network analysis difference-in-differences based on Propensity Score Matching(PSM-DID)
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东方经济学,经济拓扑学,经济进化论和循环经济 被引量:6
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作者 张一方 《吉首大学学报(自然科学版)》 CAS 2011年第1期98-104,共7页
在经济拓扑学中,经济均衡状态是静态经济学的平衡稳定态区域,经济过程分析是动态经济学,由定性分析理论讨论了经济学中的稳定性及经济变化曲线.基于东方经济学的生克原理的数学,类比于生态系统进化论数学,探讨了商业和经济的进化论与动... 在经济拓扑学中,经济均衡状态是静态经济学的平衡稳定态区域,经济过程分析是动态经济学,由定性分析理论讨论了经济学中的稳定性及经济变化曲线.基于东方经济学的生克原理的数学,类比于生态系统进化论数学,探讨了商业和经济的进化论与动力学,定性分析了动态微观经济学中的各种关系和变化模式.最后讨论了中国传统农业和农村中完全的循环经济及公共选择理论. 展开更多
关键词 经济学 拓扑学 基本原理 进化论 生克 定性分析 变化模式 循环经济
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基于OSGi的自适应可进化软件框架 被引量:3
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作者 孙力军 陈德人 施敏华 《江南大学学报(自然科学版)》 CAS 2007年第2期140-143,共4页
为解决复杂多变环境中软件开发跟不上需求变化的问题,需要设计一套具有自适应能力的软件框架.在深入研究OSGi规范的基础上,将进化论引入软件开发中,采用软件架构支持增量式开发和软件类对象能够自变化的方法,来满足需求的不断变化,最终... 为解决复杂多变环境中软件开发跟不上需求变化的问题,需要设计一套具有自适应能力的软件框架.在深入研究OSGi规范的基础上,将进化论引入软件开发中,采用软件架构支持增量式开发和软件类对象能够自变化的方法,来满足需求的不断变化,最终形成了基于OSGi的自适应、可进化的软件框架. 展开更多
关键词 开放服务网关建议 自适应 进化论 适配器模式 工厂模式
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文学进化观与中国近代文学转型的内在机制
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作者 马跃敏 《许昌学院学报》 CAS 2010年第6期64-67,共4页
近代文学转型是一个重新确立中国文学体系架构的复杂过程,由进化论主导构成的文化语境成为影响这一进程的决定性因素。应对危机和对先进文学观的积极继承促使国人接受了改写进化论的策略,使之成为改良和革命的理论支撑,并在文学内在价... 近代文学转型是一个重新确立中国文学体系架构的复杂过程,由进化论主导构成的文化语境成为影响这一进程的决定性因素。应对危机和对先进文学观的积极继承促使国人接受了改写进化论的策略,使之成为改良和革命的理论支撑,并在文学内在价值系统及内容和形式诸方面引发深刻变革。文学进化论的逻辑是不成立的,文学工具主义的策略失控,革命意识和全盘西化的思维模式等弊端也日益引起学者的警觉。 展开更多
关键词 进化论 文学转型 语境 逻辑 思维模式
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TRIZ TECHNOLOGY FORECASTING AS QFD INPUT WITHIN THE NPD ACTIVITIES 被引量:16
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作者 CoulibalySolomani HuaZhongsheng +1 位作者 ShiQin WangWei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第2期284-288,共5页
As a result of the fierceness of business competition, companies, to remaincompetitive, have to charm their customers by anticipating their needs and being able to rapidlydevelop exciting new products for them. To ove... As a result of the fierceness of business competition, companies, to remaincompetitive, have to charm their customers by anticipating their needs and being able to rapidlydevelop exciting new products for them. To overcome this challenge, technology forecasting isconsidered as a powerful tool in today's business environment, while there are as many successstories as there are failures, a good application of this method will give a good result. Amethodology of integration of patterns or lines of technology evolution in TRIZ parlance ispresented, which is also known as TRIZ technology forecasting, as input to the QFD process to designa new product. For this purpose, TRIZ technology forecasting, one of the TRIZ major tools, isdiscussed and some benefits compared to the traditional forecasting techniques are highlighted. Thena methodology to integrate TRIZ technology forecasting and QFD process is highlighted. 展开更多
关键词 Theory of inventive problem solving (TRIZ) Quality function deployment(QFD) Technology forecasting patterns/lines of technology evolution
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大规模演化知识网络中的关联推理 被引量:6
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作者 赵泽亚 贾岩涛 +2 位作者 王元卓 靳小龙 程学旗 《计算机研究与发展》 EI CSCD 北大核心 2016年第2期492-502,共11页
网络大数据时代的到来使得知识网络中时空信息越来越丰富.现有的知识网络描述模型对知识的时空信息刻画不足.研究证明,利用网络中知识的时空信息以及相关性,能够提高网络中知识间的关联推理的准确率.针对以上问题,首先提出了一种包含时... 网络大数据时代的到来使得知识网络中时空信息越来越丰富.现有的知识网络描述模型对知识的时空信息刻画不足.研究证明,利用网络中知识的时空信息以及相关性,能够提高网络中知识间的关联推理的准确率.针对以上问题,首先提出了一种包含时空信息的演化知识网络表示模型,然后研究在该网络模型上的关联推理问题,提出了一种基于背包问题的知识间关联推理方法.在多个数据集上的实验证明了所提出的关联推理方法的有效性以及对大规模知识网络的适应性. 展开更多
关键词 关联推理 演化知识网络 背包问题 链接延展模式 知识库
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Sedimentary characteristics and processes of the Paleogene Dainan Formation in the Gaoyou Depression, North Jiangsu Basin, eastern China 被引量:2
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作者 Xia Zhang Chun-Ming Lin +3 位作者 Yong Yin Ni Zhang Jian Zhou Yu-Rui Liu 《Petroleum Science》 SCIE CAS CSCD 2016年第3期385-401,共17页
In this paper,the type,vertical evolution,and distribution pattern of sedimentary facies of the Paleogene Dainan Formation in the Gaoyou Depression of the North Jiangsu Basin are studied in detail.Results show that fa... In this paper,the type,vertical evolution,and distribution pattern of sedimentary facies of the Paleogene Dainan Formation in the Gaoyou Depression of the North Jiangsu Basin are studied in detail.Results show that fan delta,delta,nearshore subaqueous fan,and lacustrine facies developed during the Dainan Formation period and their distribution pattern was mainly controlled by tectonics and paleogeography.The fan delta and nearshore subaqueous fan facies predominantly occur in the southern steep slope region where fault-induced subsidence is thought to have created substantial accommodation,whereas the delta facies are distributed on the northern gentle slope which is thought to have experienced less subsidence.Finally,the lacustrine facies is shown to have developed in the center of the depression,as well as on the flanks of the fan delta,delta,and nearshore subaqueous fan facies.Vertically,the Dainan Formation represents an integrated transgressiveregressive cycle,with the E2d1being the transgressive sequence and the E2d2being the regressive sequence.This distribution model of sedimentary facies plays an important role in predicting favorable reservoir belts for the Dainan Formation in the Gaoyou Depression and similar areas.In the Gaoyou Depression,sandstones of the subaqueous distributary channels in the fan delta and the subaqueous branch channels in the delta are characterized by physical properties favorable for reservoir formation. 展开更多
关键词 Sedimentary facies Distribution pattern Sedimentary evolution Dainan Formation Gaoyou Depression North Jiangsu Basin
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NUMERICAL STUDIES FOR A MODEL DESCRIBING COMPLEXITY
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作者 黄欣 刘曾荣 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第8期767-770,共4页
A simple model based on the discussion for infinite dimensional system is introduced to investigate the dynamical complexity for continous system.By using numerical. methods,we show the dynamical behaviors of the maod... A simple model based on the discussion for infinite dimensional system is introduced to investigate the dynamical complexity for continous system.By using numerical. methods,we show the dynamical behaviors of the maodel model appear tocorrespond to universal language and context-senitive language. 展开更多
关键词 complexity. evolution of pattern numerical method
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Deconstruction and Reconstruction—The Formation and Evolution of the Pattern of Discourse of May Fourth Literature
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《Social Sciences in China》 2001年第1期163-174,共12页
关键词 Deconstruction and Reconstruction The Formation and evolution of the pattern of Discourse of May Fourth Literature
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Prediction and Regulation of Delamination at Flexible Film/Finite-Thickness-Substrate Structure Interfaces
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作者 Yutang Zhou Yunlong Xu +1 位作者 Haoran Gong Chenyu Wang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2024年第2期238-251,共14页
Regulating the surface instability of thin film/substrate structures has been successfully applied to prepare new ductile electronic devices.However,such electronic devices need to be subjected to external loads durin... Regulating the surface instability of thin film/substrate structures has been successfully applied to prepare new ductile electronic devices.However,such electronic devices need to be subjected to external loads during operation,which can easily induce delamination of the thin-film electronic device from the substrate.This study aims to investigate the instability characteristics of hard films on flexible substrate surfaces from theoretical analysis and numerical simulation perspectives.Considering finite-thickness substrates,this paper establishes theoretical models for pure bending,bent wrinkle,partial delamination,and total delamination buckling of film/substrate structures based on the nonlinear Euler–Bernoulli beam theory and the principle of minimum energy;then the effects of material and geometric parameters of the structure,interfacial adhesion strength,and pre-strain on the evolutionary path of the four patterns are discussed.The study results show that:the greater Young’s modulus of the substrate is,the larger the parameter region where partial delamination of the film/substrate structure occurs,and the smaller the parameter region where bent wrinkle occurs.By varying Young’s modulus,thickness of the film and substrate,interfacial adhesion coefficient,and pre-strain,the buckling pattern of the structure can be predicted and regulated.The parametric design intervals for each pattern are summarized in the phase diagram.The results of this paper provide theoretical support for the design and reliability evaluation of flexible electronic devices. 展开更多
关键词 Thin film/finite-thickness-substrate structure DELAMINATION Surface instability pattern evolution
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High-amplitude pressure fluctuations of a pump-turbine with large head variable ratio during the turbine load rejection process
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作者 FU XiaoLong LI DeYou +2 位作者 SONG YeChen WANG HongJie WEI XianZhu 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2023年第9期2575-2585,共11页
Large-head variable-amplitude pump turbines(PTs) encounter serious transient hydraulic instability issues. To explore the evolution mechanisms of pressure fluctuations(PFs) and flow patterns inside large-head variable... Large-head variable-amplitude pump turbines(PTs) encounter serious transient hydraulic instability issues. To explore the evolution mechanisms of pressure fluctuations(PFs) and flow patterns inside large-head variable-amplitude PTs, the load rejection process(LRP) was investigated using a one-and three-dimensional coupled flow simulation approach. The temporal,spatial, and frequency characteristics of the fluctuating pressures were analyzed for four monitoring points using a combined time-frequency analysis approach. The results indicated that PFs during the LRP of large-head variable-amplitude PTs had a new fluctuation frequency component related to Dean vortices(DVs) in the volute, in addition to the common fluctuation frequency components related to rotor-stator interaction phenomena and local backflow vortices near the impeller inlet. The PF frequency component existed throughout the LRP and had a significant influence on the transient maximum pressure at the volute end. This study provides a useful theoretical guide for the design and optimization of large-head variable-amplitude PTs. 展开更多
关键词 large-head variable-amplitude pump turbine load rejection process 1D-3D flow simulation pressure fluctuation flow pattern evolution
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